Invertebrates are the most abundant creatures on earth, crawling, flying, floating, or swimming in virtually all of Earth's habitats, from townhouses to tropical rainforests. Yet most of us rarely notice them unless they're in our gardens or on our dinner plates.

Invertebrates—creatures without backbones—are nature's unsung heroes, quietly playing vital roles in earth's ecosystems. About 99 percent of all known living species are invertebrates. Vertebrates—fish, amphibians, reptiles, birds, and mammals—make up a tiny fraction of life on earth. more about the silent majority

It is nearly impossible to go a day without encountering one of the million species of arthropods. Most of them are insects, and many others are spiders.